An artificial neural network is an information processing system modeled on a biological neural network. A computer having a higher performance than a conventional Neumann computer is expected to be provided by utilizing the artificial neural network, and in these years, a variety of researches on an artificial neural network formed over an electronic circuit have been carried out.
In the artificial neural network, units which resemble neurons are connected to each other through units which resemble synapses. By changing the connection strength, a variety of input patterns are learned, and pattern recognition, associative storage, or the like can be performed at high speed. Furthermore, Non-Patent Document 1 discloses a technique relating to a chip having a self-learning function with the artificial neural network.